Lawn Grubs

Posted by LNA Master Landscapers Association
on 17 April 2016

In Australia, lawn grubs are typically most active during the warmer months of October to March, meaning you may now be encountering some very damaged lawns in April. The grubs create brown patches in lawns where they have eaten all the roots of the grass.

What are lawn grubs?
Lawn grubs are the larvae of small, greyish-brown moths. These moths are often seen hovering in groups around dusk looking for the healthiest lawns to lay their eggs in. Within 2-5 days of being laid the eggs become grub larvae and it is these larvae caterpillars that damage lawns. The caterpillars spend 18-24 days chewing the grass before metamorphosing into pupae. The pupae become moths around 5-8 days later and begin to lay their own eggs, perpetuating the cycle.

Lawn types effected
Couch, Fescue and Kikuyu lawns are at most risk of grub attacks. Buffalo lawns, such as Sir Walter, are not usually badly damaged and can recover relatively quickly.

Signs you may have lawn grubs
Some of the signs that may indicate the presence of lawn grubs include:

Brown patches in lawns that do not turn green again - the lawn will peel back like a carpet because the grubs have eaten all the roots of the grass

Increased bird activity - lawn grubs are great food for many bird species

A spongy lawn.

How to treat lawn grubs
Fortunately, there are pest control products on the market that can treat lawn grubs. It can take a while to break the cycle so it is recommended that:

An agent that remains in the soil for a longer period is applied, for example Lawn Solutions Australia's Grub Guard

You consider the need to use a second application of the product to ensure the cycle has been completely destroyed.